Fuel containing a solvent extract pour point depressant



Patented Mar. 7, 1967 1 3,308,051 FUEL CONTAINING A SOLVENT EXTRACT POURPOINT DEPRESSANT Eugene M. Fauber, Hammond, Ind, assignor to SinclairResearch, Inc., New York, N.Y., a corporation of Delaware No Drawing.Filed June 1, 1964, Ser. No. 371,820 2 Claims. (Cl. 208-15)Thisinvention is directed to distillate fuel oil compositions having animproved pour point. More particularly, the invention relates to adistillate fuel oil boiling above the gasoline range containing as anadditive a select amount of a deasphalted residual oil.

When fuels are to be used or stored under low temperatures, it hasbecome common practice to incorporate small amounts of a pour depressor.I have now discovered that a deasphalted residual oil when added to thedistillate fuel in a particular amount reduces the pour point of thefuel. In addition, the novel additive of the invention improves thecloud point and color stability of the fuel.

The deasphalted residual oil of the present invention is the oil'extractboiling primarily in the rang-e of about 750 F. to 1050 F. at 40%overhead and having a viscosity at 210 F. of at least about 200 F. up tosay about 250 F. or more, removed from Mid-Continent 'asphalticresiduals by solvent extraction with a paraffinic hydrocarbon solventhaving about 3 to 5 carbon atoms.

The Mid-Continent feeds from which the deasphalted residual oil isobtained comprise petroleum asphalt residua which may be exemplified byvacuum residua, atmospheric residua, tars, pitches, etc. boilingprimarily above about 750 F. or even above about 800 F. The preferredresidual feed often has an API gravity in the range of about 8 to 14,Conradson carbon content in the range of about 7 to 12 weight percentand a viscosity above about 1600 SUS at 210 F., preferably up to about2200 SUS at 210 F.

The conditions used in the solvent extraction deasphalting step can varydepending on the boiling point of the residual feed and are ordinarilyselected to provide a deasphalted extract oil yield of at least about35% up to 60% or more. The minimum temperature used in the solventextraction will be the softening point of the asphalt feed while themaximum will be the boiling temperature of the solvent at the pressureused. The extraction step is frequently performed at a temperature ofabout 100 to 200 F. There may be a temperature gradient in thedeasphalting step with the highest temperature found at the deasphaltedoil (extract phase) outlet. A temperature gradient of about 25 F. to 50F. is preferably maintained. Normal operating pressures should be higherthan the vapor pressure of the solvent system used at the temperature ofoperation. The extraction can be carried out as a single or plurality ofextractions in one vessel or a plurality of vessels.

The hydrocarbon solvent used for the extraction includes propane,butane, pentane, etc. or combinations thereof. The preferred solvent ispropane. After the contacting, the mixture of residual feed and solventis separated into an extract phase containing the solvent and extractedoil components and a raffinate or asphalt bottoms phase. The two phasesare separately withdrawn and the hydrocarbon solvent removed, forinstance, for vaporization to provide the deasphalted extract oil of theinvention. The amount of hydrocarbon solvent employed in the extractionmay be within the range of about 2 to 20 volumes of solvent per volumeof asphalt residual feed, preferably about 5 to 9 volumes of solvent pervolume of feed.

The amount of deasphalted extract oil added to the fuel oils of theinvention is important. It has been found essential to add about 1, e.g.about 0.75 to 1.25, volume percent of the deasphalted extract oil inorder to reduce the pour point of distillate fuel oils. Amounts of about0.5 and 2.5 volume percent fail to reduce either the pour point or cloudpoint.

The hydrocarbon fuels which are improved in accordance with the presentinvention include the normally liquid petroleum distillates boilingprimarily above the gasoline range and include, for example, dieselfuels, heating oils, etc. These oils are usually petroleum middledistillates which generally boil primarily in the range of about 250 to750 F., and commonly have relatively high pour points, for instance, atleast at -10 F. or higher. The oils can be in their relatively crudestate or they can be treated in accordance with well-known commercialmethods such as acid or caustic treatment, solvent refining,hydrotreating, etc. The fuel oils can contain straight run distillatefuel oils, catalytically or thermally cracked fuel oils or mixtures ofstraight run fuel oils, naphthas and'the like with cracked distillatestocks. The cracked materials will frequently be about 15 to 20 volumepercent of the fuel.

The following examples are included to further illustrate the presentinvention.

Example I Four Mid-Continent asphalt residual fractions, A, B, C and D,boiling above 740 F. and having the characteristics shown in Table Ibelow were extracted countercurrently in a tower with propane under theextraction conditions shown in Table I. Tests on the deasphalted extractoils (D.A. oils) obtained are also summarized in Table I.

TABLE I A B C D Feedstock to Propane Unit:

APi Gravity 15. 5 14. 5 12. 6 12. 6 SSU VlS. at 210 F 800 1,400 2,0722,072 Propane Unit Operating Conditions:

Solvent; to Oil Ratio 7/1 8/1 6. 7/1 7.3/1 Temperature, F.:

Top 165 160 147 155 Bottom 125 123 109 109 Approx. Stag 2 2 2 2 FeedRate, b./d. 5,000 5, 000 0,050 5,500 Tower Diameter, ft 10 10 10 10Yield of Deasphalted Extract Oil, Vol. percent 55 50 42. 6 41. 0 Testson Deasphalted Extract Oils:

API Gravity- 24. 3 23. 2 22. 4 22. 8 SSU vis. at 210 F 194 231. 7 204. 0Pour Point, 120 120 Clay Gel Analysis:

saturates 53. 9 52. 4 47. 4 49. 1 Aromatics. 38. 6 37. 7 40. 8 40. 2Resms 7. 5 9. 9 11.8 10. 7

The deasphalted extract oils thus obtained were each added in amounts of0.5%, 1.0% and 2.5% by volume to a No. 2 fuel composed of 65% gas oil,31% light cycle oil and 5% kerosene, and having a distillation range offrom 305 to 618 F. The pour, cloud and haze points of the deasphaltedextraction oil-containing fuel samples were determined. The results aregiven in Table II and include the pour and cloud point of the No. 2 fuelfor purposes of comparison.

TABLE II Blend Number Composition of Blend:

N0. 2 Fuel (Neat), Vol. Percent D.A. Oil A, Vol. Percent D.A. Oil 13,Vol. Percent". DlA. Oil 0, Vol. Pereent D.A. Oil D, Vol. Percent.

Tests on Blends:

Haze Point, F Cloud Point, F .r. Pour Point, F .t

" Too much haze to get cloud point.

The data of Table II illustrates the light deasphalted oils asrepresented by deasphalted oils A and B fail to improve pour point. Thedata also demonstrates the necessity of about 1.0% of the additive toobtain any significant reduction in pour or cloud point. Lastly, thedata shows that the heavier deasphalted oils C and D are more efifectivethan the lighter extract oils.

Example 11 The ASTM color of the No. 2 fuel containing 1.0% ofdeasphalted extract oil C of Example I was taken at the time ofincorporation and again after a 7-month period. For comparison, the ASTMcolor of the original No. 2 fuel (without additive) was taken at thebeginning and end of the same period. The results were as follows:

A ST M C olor Orig nal Alter 7 Months No. 2 Fuel (no additive) 1 3. No.2 Fuel plus 1% deasphalted oil (1. 2 3

The data shows that the deasphalted extract oil additive of theinvention possesses color stabilizing characteristics.

2. A fuel composition of claim 1 wherein the extract is obtained from apetroleum residual having an API gravity of about 8 to 14, a Conradsoncarbon content of about 7 to 12 weight percent, and a viscosity SUS at210 F. of about 1600 to 2200.

References Cited by the Examiner UNITED STATES PATENTS 2,339,898 1/1944White et al. 20819 2,664,338 12/1953 Winterhalter 208-15 2,725,34511/1955 Binovic et al. 208l9 FOREIGN PATENTS 178,627 3/1962 Sweden.

DANIEL E. WY MAN, Primary Examiner.

P. E. KONOPKA, Assistant Examiner.

1. A FUEL COMPOSITION OF IMPROVED POUR AND CLOUD POINT CONSISTINGESSENTIALLY OF A DISTILLATE HYDROCARBON FUEL BOILING ABOVE THE GASOLINERANGE HAVING INCORPORATED THEREIN ABOUT 0.75 TO 1.25 VOLUME PERCENT INTHE RANGE OF ABOUT 750* TO 1050*F. AT 40% OVERHEAD AND HAVING AVISCOSITY AT 210*F. OF AT LEAST ABOUT 200*F. OBTAINED BY EXTRACTION FROMA MID-CONTINENT PETROLEUM RESIDUAL BOILING ABOVE ABOUT 750*F. WITH APARAFFINIC HYDROCARBON SOLVENT OF 3 TO 5 CARBON ATOMS.